Article and screw anchor-supported, load-bearing pad therefor

ABSTRACT

A plurality of upright screw anchors are embedded in the ground to support a lightweight, formed, corrosion-resistant base pad of fiber glass filled polyester resin material and an article such as a transformer, switchgear, air conditioning unit or other load disposed on the top surface of the pad. The lowermost helix carrying ends of the anchors are driven below the frost and seasonal moisture lines of the ground to assure that the anchors provide a stable support for the pad and article. The lowermost edge of the pad may be buried while leaving the top surface thereof exposed to provide an aesthetically pleasing installation and to hinder access to cables and the like in the formed hollow area underneath the pad. Such area may be filled with earth to further impede unauthorized access. The anchors and pad are especially suited for packaging with the article as a unit on a pallet therefor for ease of distribution.

United States Patent [1 1 Grannis, 111

[ Oct. 15,1974

[7 51 Inventor: Charles 0. Grannis, lll, Centralia,

[73] Assignee: A.B. Chance Company, Centralia,

221 Filed: May 17, 1972 211 Appl. No.: 253,954

[52] US. Cl 52/27, 52/157, 52/169,

248/19, 248/156, 248/346 [51] Int. Cl E04d 5/74, E04f 19/00 [58] Field of Search 52/27, 36, 157, 309, 295,

3,713,620 l/l973 Tkach 52/295 X FOREIGN PATENTS OR APPLICATIONS 622,354 12/1962 France 52/126 Primary Examiner-Henry C. Sutherland Attorney, Agent, or Firm-Schmidt, Johnson, Hovey & Williams 57 ABSTRACT A plurality of upright screw anchors are embedded in the ground to support a lightweight, formed, corrosion-resistant base pad of fiber glass filled polyester resin material and an article such as a transformer, switchgear, air conditioning unit or other load disposed on the top surface of the pad. The lowermost helix carrying ends of the anchors are driven below the frostand seasonal moisture lines of the ground to assure that the anchors provide a stable support for thepad and article. The lowermost edge of the pad may be buried while leaving the top surface thereof exposed to provide an aesthetically pleasing installation and to hinder access to cables and the like in the formed hollow area underneath the pad. Such area may be filled with earth to further impede unauthorized access. The anchors and pad are especially suited for packaging with the article as a unit on a pallet therefor for ease of distribution.

5 Claims, 9 Drawing Figures PAIENImnm 1 51524 SHEEI 10F 2 PAIENTED BC? I 51914 SHEEI 2 OF 2' This invention relates to foundation structure which is appropriate for various and sundry types of articles and loads including, but not limited to, electrical apparatus such as transformers and switchgear, air conditioning units, and small utility sheds. The invention is particularly well suited for electrical transformers used in connection with underground distribution systems.

, With the increase in recent years of underground residential distribution systems because of their inherent advantages, the need has increased for providing safe and .efficient transformer units which receive distribution voltage from underground lines at a high voltage level and step the voltagedown to a usable'household level of l/240 volts. Such transformer units (15 KV being a typical class) are generally disposed at ground level or slightly thereabove. The above-ground position of the units presents a number of problems, however,

not the least of which is the fact that children are attracted to the transformers and oftentimes out of curiosity attempt to gain access to the interiorthereof. In addition, the units are vulnerable to vandals. In spite of extensive measures taken to insure the safety of those who come in contact with the above ground transformers, cases have been reported wherein injurieshave occurred as a result of determined efforts of children or vandals to overcome the safe-guards inherent in such units. For example, it is not uncommon for injuries to arise as a result of children making an effort to force coat-hangers or the like'between narrow crevices and gaps between proximal, intermittently interengaging,

outer housing components of the unit, whereupon the coat hanger may contact an energized terminal of the transformer, resulting in electrocution. Exemplary in this respect are instances where piecesof wire have been inserted beneath the lower edge of the transformer and the support therefor.

In addition to the safety problems presented, installation and maintenance of the transformer units is an especially important consideration. In the past it has been common practice to support such unitson concrete slabs which were either poured at the installation site or precast for shipment thereto. The precast slabs were extremely heavy, making handling thereof difficult, and required extensive soil preparation at the installations site such as digging, leveling, and tamping of the soil in preparation for the slab. Similar problems were encountered when the slabs were poured in place. Moreover, by resting the concrete slab directly on the ground, the slab was subject to dislodgement from its resting place as a result of seasonal temperature variations producing frost heave and changes in the moisture content of the ground beneath the'slab which caused tilting thereof. Another problem encountered was the inherent unevenness of the top surface of such concrete slabs. This unevenness caused gaps to appear between the bottom of the transformer body and the slabs, thus inviting vandals or curious children to insert elongated objects, such as coat hangers or metal pieces, into such gaps, leading to possible physical injuries.

It is, therefore, the primary object of the present invention to provide foundation structure suitable for use in a variety of applications to free standing loads of diverse sizes and descriptions, which structure is capable of providing extremely stable support without great weight or expense.

Another important object of the present invention is to provide a method and apparatus particularly suited for installations of transformers used in connection with underground distribution systems, such method and apparatus being designed to reduce the handling, maintenance and environmental problems inherent in use of precast or poured in place concrete slabs previously used, as well as to minimize the hazards to personal safety of children and other unauthorized persons attracted to the transformer.

As a corollary to the aforesaid object, an important aim of the instant invention. is to provide a relatively light-weight base pad for the transformer constructed of corrosion-resistant material having a high strengthto-weight ratio which is supported therebeneath by a plurality of vertically disposed, horizontally spaced anchors embedded within the ground, thus decreasing material and installation costs,

Yet another important object of the present invention is to provide a base pad as above described having a substantially flat, smooth upper surface to effect an essentially tight conforming seal with the bottom of the transformer. I

Also an object of the invention is the provision of a transformer assembly as described which is especially suitable for storage and distribution on a pallet therefor in that the transformer andpad may be secured directly to the pallet and the anchors mounted alongside the same, thus providing a relativelightweight package which may be easily handled using conventional equipment available to utility line construction crews. In the drawings:

FIG. 1 is a perspective view of an article, base pad and screw anchors packaged as a unit on a pallet for shipment or storage, the article chosen for purposes of illustration being an electrical transformer; 1

FIG. 2 is a fragmentary, elevational view of the unit installed, with parts broken away and shown in cross section for clarity;

FIG. 3 is a fragmentary, substantially vertical, crosssectional view of the unit taken along line 3-3 of FIG.

FIG. 4 is a plan view of the bottom side of the transformer base pad on a reduced scale, the upper ends of the anchors being fragmentarily shown and the location of the transformer body thereabove being indicated by dash lines;

FIG. 5 is an enlarged, fragmentary, detail view of an adjustable mounting clip on one corner of the front frame of the transformer body; I

FIG. 6is an enlarged, top plan view of one of the anchors of the transformer unit;

FIG. 7 is a fragmentary, vertical cross-sectional view through the installation site, illustrating the manner in which the anchors are installed;

FIG. 8 is a fragmentary, perspective view of the installation site on a reduced scale illustrating the installation process; and

FIG. 9 is a perspective view of the completely installed unit on a reduced scale.

In FIG. 1 a pallet 10 carries an article 12 (shown by way of example as an electrical transformer), a foundation base pad 14 for the article or transformer 12, and three elongated foundation anchors 16. Each anchor 16 includes a rigid shaft 18 having a normally lowermost end which may be pointed, the shaft 18 having a short surface-increasing helix 20 adjacent such lowermost end and a circular plate 22 secured to its upper end provided with four circumferentially spaced openings 24 (FIG. 6). The openings 24 are adapted to receive corresponding prongs 26 of an installation tool 28 (FIG. 7) which, in turn, is adapted to be mounted on one end of an elongated driving bar 30, although it is to be understood that other forms of driving means could be provided.

The transformer 12 chosen for illustration is of the IS KV class, although it is to be understood that the principles of the present invention are not limited in any respect to a transformer of such size. The body of transformer 12 comprises as its major component a tank 32 filled with a suitable liquid 34 such as oil, and containing coil structure (not shown) which is suitably connected to the primary and secondary terminals 36 and 38 respectively which project outwardly from the front plate 40 of tank 32. A bottom plate 42 (FIG. 2) is welded to the tank 32, forming the bottom thereof, and has a downturned, vertically extending flange 44 along both sides of tank 32 and across the back thereof, the flange 44 presenting a lowermost, narrow edge. A pair of fore-and-aft extending angles 46 (FIG. 3) are welded to plate 42 to brace the latter.

A relatively thin metal strip 48 (FIGS. 2, 3 and 8) is welded to front plate 40 adjacent respective sides and the top thereof and in laterally spaced relationship with an inturned flange 50 about the same three boundaries of front plate 40. A three-sided open frame 52, shown best in FIG. 8, is bolted to tank 32 at the lower front corners thereof and has a three-sided, short, upstanding wall 54 set-in from the outer margins of frame 52. The rearmost portions of wall 54 are disposed on the outside of strip 48 in proximal relationship therewith (FIG. 3) to avoid closing the space between flange 50 and strip 48 at those locations.

A hood 56 is swingably joined to the top stretch of flange 50 by a pair of hinges 58 which support hood 56 for swinging movement into and out of covering relationship to the terminals 36, 38, and frame 52. An L- shaped strip 60 (FIGS. 2-and 3) is welded to the inside of hood 56 along all of the edges thereof in a position to fit between the strip 48 and flange 50 on tank 32 and inside of the short wall 54 on frame 52 when hood S6 is closed, as shown throughout the Figures. Thus, a tamper-resistant construction is presented which essentially eliminates unauthorized entry of slender objects, such as coat hangers, between hood 56 and tank 32 or frame 52.

Base pad 14 is molded from a corrosion-resistant material having a high strength-to-weight ratio such as polyester resin reinforced with fiber glass mat. Preferably, pad 14 is compression molded with the fiber glass fill oriented in random fashion to thus present an exceptionally strong product which resists cracking. Pad 14 presents a relatively thin, rectangular top panel 62 having an extremely smooth, flat, uppermost surface, the panel 62 also being provided with a plurality of laterally extending reinforcing and locating ribs 64 across the bottom thereof, as shown in FIG. 4. Additional ribs (not shown) may be provided forwardly of the frontmost rib 64 extending transversely of the latter. Panel 62 has a continuous, peripheral sidewall 66 which merges with panel 62 and is inclined slightly with respect thereto. As will hereinafter become clear, sidewall 66 functions as additional reinforcing means for the panel 62, as well as a skirt to preclude access to the underside of panel 62. A large, hollow area is thus defined by the continuous sidewall 66 and panel 62 below the latter, and a relatively short, flat peripheral lip 68 projects outwardly from sidewall 66 in substantial parallelism with panel 62.

Panel 62 is provided with a rectangular cableway 70 which receives the underground cables generally denoted by the numeral 72 when the transformer and foundation unit is installed. Optionally, a pair of nuts 74 may be embedded within panel 62 in the front portion thereof, each of which is adapted to receive a mounting bolt 76 (FIGS. 2 and 5) which secures a corresponding hold-down clip 78 across the corners of the sill 80 along the bottom of frame 52. Each clip 78 may be provided with an elongated slot 82 therein which receives bolt 76 to compensate for transformers of different sizes. Similarly, an L-shaped angle clip 84 may be provided at option at each corner of tank 32 along with an accompanying hold-down bolt 86 to join the transformer I2 and pad 14 at those locations.

Installation of the transformer and foundation unit may be easily carried out in the following steps. Only a minimal amount of site preparation is necessary as opposed to those preparatory steps previously required in installations where concrete slabs were utilized to support the transformer. As illustrated in FIGS. 7 and 8, the anchors 16 are driven into the ground in a horizontally spaced, vertically disposed manner forming respective corners of a triangle adjacent the cables 72 which project above the surface of the ground. Each anchor 16 is driven into the ground by a digger-derrick or like machine until the helix 20 thereof is disposed below the frost line and seasonal moisture line of the location, leaving a portion of the uppermost end of shaft 18 and plate 22 disposed a short distance above the surface of the ground as shown by the left anchor in FIG. 7. The particular spacing of the anchors 16 is dependent upon the size of the pad 14 and transformer 12.

After installation of the anchors 16, the earth encompassing the cables 72 and anchors 16 may optionally be built up to present a short mound area 88, as shown in FIG. 8, which conforms to the dimensionsof the hollow area of pad 14 below panel 62 thereof. If such a mound area 88 is constructed, it is important that the plates 22 of anchors 16 remain exposed. It is also important that anchors 16 be driven to a uniform depth such that the top plates 22 thereof are disposed in a level condition with respect to one another.

Assuming for purposes of illustration that the transformer 12 has been secured to the pad 14 via holddown clips 78 and 84, the next step in the installation process is to lower the combined transformer 12 and pad 14 onto the anchors 16 as depicted in FIG. 8. For this purpose, lifting studs 90 may be threaded into opposite sides of transformer 12 to which a strap 92 or the like may be secured. Once the transformer 12 and pad 14 have been placed over the mound area 88 and on top of anchors 16, the locations of plates 22 relative to the pad 14 and transformer 12 should appear as depicted in FIGS. 2, 3 and 4 wherein it may be seen that the plates 22 are disposed within the hollow area of pad 14 bearing against the underside of panel 62 to support the transformer 12. The two front plates 22 are disposed between' the middle and front ribs 64 of pad 14,

while the third rear plate 22 is located between the middle and rearmost rib 64 extending slightly beyond the outline of the back of tank 32. This triangular pattern defined by anchors 16 could be reversed with only one of the plates 22 placed between the two forward ribs 64, but in either case it is preferred that anchors 16 be arranged such that a vertical line extended through the center of gravity of tank 32 would intersect the junction of the medians of the legs of the triangle.

The earth may then be built up around the perimeter of pad 14 covering lip 68 as shown clearly in FIGS. 2 and 3. Thus, the lower terminus of lip 68 becomes buried such that access is made more difficult to the area beneath pad 14. Moreover, the fact that the hollow area immediately below panel 62 is filled with earth contributes to the difficulty in gaining access to the cables 72 below the surface of the ground. To facilitate covering of lip 68 it is suggested that a shallow ditch may be provided about the mound area 88 within which lip 68 may be deposited upon lowering of pad 14 and transformer 12 onto the anchors 16.

The installation process is completed by connecting the cables 72 to the appropriate terminals 36 and 38, whereupon the cableway 70 may be filled with an appropriate filler material 94 to prevent rodents or other small animals from entering the warm interior of transformer 12 below hood 56. It has been found that a filler having particular utility for this purpose may be provided by a mixture of epoxy resin and soil particles, the latter contributing a certain degree of brittleness or breakability to the tiller material. Hence, the cured filler material 94 may be broken and removed from cableway 70 without difficulty if such action is ever necessary in order to service cables 72 or remove the installed unit. Once the unit is completely installed, the installation gives the outward appearance shown in FIG. 9.

It is important to note that the pad 14, because of its light weight and configuration, is extremely easy to handle, transport and store. A number of pads 14 can be nested one within the other for storage purposes, the polyester resin and fiber glass material of which the pad is constructed may be colored as desired to blend with the surroundings, and the pad 14 itself provides excellent insulation between the anchors l6 and tank 32. Moreover, it will be appreciated that installation of the complete unit is greatly facilitated since the burdensome steps of preparing the site for the pouring of a concrete slab or placement of a precast slab have been eliminated.

Also of extreme importance is the fact that the problems previously associated with heaving and tilting of transformers due to seasonal affects upon the ground, are completely eliminated by virtue of the stable support provided by anchors 16 which have the helixes 20 thereofdisposed in stable soil below the frost and moisture lines of the ground. In addition, because of the extremely smooth,flat upper surface which may be provided on pad 14, the lowermost edges of flange 44 about the bottom of tank 32 conform tightly to the upper surface in sealing relationship therewith. Thus,

1. In combination:

a relatively heavy article requiring stable groundlevel support free from tiltingor heaving such as caused by seasonal changes in environmental conditions;

a base pad for said article constructed of corrosionresistant material having a high strength-to-weight ratio,

said pad being provided with a relatively thin, normally horizontally disposed article-supporting panel section; and

a plurality of elongated, rigid anchors adapted to be embedded in the ground in horizontally spaced, upright disposition,

each of said anchors having a normally uppermost end adapted, upon installation of the anchors, to project above the surface of the ground a sufficient extent to engage and support said pad, thereby supporting said article,

said articlecomprising an electrical transformer for underground electrical distribution lines,

said panel section being provided with at least one opening therein for passage therethrough of said distribution lines into connecting relationship with said transformer, said opening having filler material therein surrounding said lines and filling the area of said opening not occupied by the lines.

2. The combination as claimed in claim 1, wherein said transformer has a lower support edge, said panel section having an outer surface conforming closely to the contour of said edge to assure continuous, conforming contact between the latter and said surface.

3. The combination as claimed in claim 2, wherein said surface is smooth and flat.

4. The combination as claimed in claim 1, wherein said filler material includes a mixture of epoxy resin and soil particles.

5. The combination as claimed in claim 1, wherein said panel section is provided with downwardly depending structure defining a hollow area beneath said section within which said uppermost ends of the anchors are disposed and blocking access to said lines. 

1. In combination: a relatively heavy article requiring stable ground-level support free from tilting or heaving such as caused by seasonal changes in environmental conditions; a base pad for said article constructed of corrosion-resistant material having a high strength-to-weight ratio, said pad being provided with a relatively thin, normally horizontally disposed article-supporting panel section; and a plurality of elongated, rigid anchors adapted to be embedded in the ground in horizontally spaced, upright disposition, each of said anchors having a normally uppermost end adapted, upon installation of the anchors, to project above the surface of the ground a sufficient extent to engage and support said pad, thereby supporting said article, said article comprising an electrical transformer for underground electrical distribution lines, said panel section being provided with at least one opening therein for passage therethrough of said distributIon lines into connecting relationship with said transformer, said opening having filler material therein surrounding said lines and filling the area of said opening not occupied by the lines.
 2. The combination as claimed in claim 1, wherein said transformer has a lower support edge, said panel section having an outer surface conforming closely to the contour of said edge to assure continuous, conforming contact between the latter and said surface.
 3. The combination as claimed in claim 2, wherein said surface is smooth and flat.
 4. The combination as claimed in claim 1, wherein said filler material includes a mixture of epoxy resin and soil particles.
 5. The combination as claimed in claim 1, wherein said panel section is provided with downwardly depending structure defining a hollow area beneath said section within which said uppermost ends of the anchors are disposed and blocking access to said lines. 